Steam-generator



(No Model.) 3 Sheets-Sheet 1.

N. W. PRATT. STEAM GENERATOR.

No. 428,632. Patented May 27, 1890.

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WITNESSES. f VVE/VIOR. Z. (R. HEM M )fi fmww 5 {7w ATTORNEY.

(No Model.) 3Sheets-Sheet 2-.

'N. w. PRATT. STEAM GENERATOR.

No. 428,632. Patented May 27-, 1890.

WITNESSES. fi/NVENTOR. a/A f g Q M ATTORNEY.

(No Model.) 3Sheets-Sheet 3.

N. W. PRATT. STEAM GENERATOR.

No. 428,632. PatentedMay 27, 1890.

WITNESSES. v INVENTOR.

ATTORN I".

UNITED STATES I PATENT OFFICE.

NAT. WV. PRATT, OF BROOKLYN, NElV YORK.

STEAM-GENERATOR.

SPECIFICATION forming part of Letters Patent No, 428,632, dated May 27, 1890.

Application filed January 28, 1888. Serial No. 262,211. (No model.)

T0 65 whom it ntay concern.-

Be it known that I, NAT. W. PRATT, a citizen of the United States, residing at Brooklyn, county of Kings, State of New York, have invented certain new and useful Improvements in Steam-Generators, of which the following is a specification.

In order that others may understand and use my invention, I will first proceed to de scribe a structure embodying it, and subsequently will point out in the claims its novel characteristics.

Referring to the accompanying drawings, in which corresponding letters indicate like parts, Figure 1 is a longitudinal vertical section of a battery of boilers constructed according to my invention; Fig. 2, a front elevation, partly in section, on the line a: m, Fig. 1; Fig. 3, a longitudinal vertical section of the lower portion of the foundation; and Fig. at, a ground plan of the foundation, taken partly in section, on the line y y, Fig. 1.

A A A are groups of generating water-tubes, all connecting vertically by serpentine headers a at each end thereof, and by means of nipples b and 0, respectively, with the connecting-boxes E of the water-columns B and the drum manifolds L of the drums D.

O O are the combustion spaces or chambers between the said groups of generatingtubes. The serpentine headers a interlock, as seen in Fig. 2, and form walls within which the draft-course is confined, the spaces between the nipples 0 being closed by fire-brick filling c, or in the instance of the outer ends of the structures the draft being confined by the boiler-fronts and doors M. The tubes A are inclined in the manner common to boilers of this class, so that upward circulation is promoted by the heat, delivering the current from the tubes through the central assemblage of headers 0. to the mid portion of the drum or drums D, and thence downward through the water columns or'legs B. The space or chamber N intermediate to the sections is cut off from the draft-flue and combustion-chambers by the fire-brick partition 0, and serves the purpose of access to the hand-holes P, opposite the tubes, whereby the same may be cleaned or repaired. The drum D, I prefer to make continuous over the sets of groups of tubes set at opposite angles. Each series of groups I provide with a separate furnace I, each of which communicates with the common smoke-flue II. The water-legs B act as supports for the outermost ends of the tubular structures, and the drums D are supported on the foundation by the vertical I-beams F and cross-beams G. The differences of expansion between the vertical water-legs B and beams F are yielded to by the offset curvatures or necks (Z in said water-legs, which by the ductility of the metal will bend to the limited degree required and avoid lifting or disturbing the drums from their fastenings. The ,water-legs B are adapted by their large diameter and lower extensions B below the point of final water-circulating delivery .(through connecting-boxes E) to separate the heavier impurities by gravity at each downward circulation of the water after passage through the generating portions of the boiler. The said extensions B act as sediment-repositories, wherefrom the accumulations are occasionally (or continuously) withdrawn by means of suitable blow-off pipes e e. The feed-wateris admitted to the lower portions of the drums D by pipes (not shown) and the generated steam delivered by pipes K, which latter extend through the drums and are adapted by openings at their upper sides, as at f, Fig. 2, to avoid priming.

H is the horizontal draft-flue conducting to the smoke-stack or chimney. The draft passes from the furnaces I continuously upward and directly out between the drums and through connections J to the flue II.

The construction shown is manifestly adaptcd to a battery of boilers to any desired capacity or to a single boiler, and the combustion-spaces may be employed in any number other than that shown. The volume which the spaces O should have is governed by the number of tubes intervening, and, furthermore, the volume of the said spaces relatively to each other may be variedas, for instance, in diminishing order-according to remoteness from the furnace.

It is evident that one half the boiler shown may be used alone without changing the character of the invention, or that the combinanation of two such independent halves would be the exact equivalent of the ecmstruetiou herein shown, as it is not necessary for the success of the invention that the drum 1) should be continuous.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is

1. In a water-tube steam-boiler, the combination of a series of groups of inclined tubes arranged at oppositeinelines, a drum or drums above and connected with said tubes, a series of furnaces communicating with a common smoke-flue, and a common chamber between the groups of tubes, substantially as herein specified.

52. In a water-tube boiler, the con'lbination of a series of groups of inclined tubes arranged at opposite inclines, a series of furnaces connecting with a common smoke-flue,

and a common chamber between the groups of tubes, substantially as herein described.

I Asa structure for a sectional water-tube steam -g'enerator, the combination, with a group or vertical succession of groups of inetined enerating-tubes, the horizontal steamreeeivin drum or drums above said tubes having fixed support, as by vertical and transverse beams F and G, of the yielding; waterleg connections, as having curved necks d, and transverse connecting-boxes, as E, adapted to support and connect with the lower ends of said inclined tubes and to connect with said fixed drums irrespective of expansion or contraction of said water-legs.

NAT. \V. PRATT. \Vitnesses:

H. E. BUNKER, CHAS. L. )I'onnnn. 

